Recently, e-WOM has become more and more influential on consumers' choice of products due to the increase of online shopping. Electronic word of mouth has features such as tangibility, anonymity, and space-time, so that people can share their opinion about the product with others and affect a wide range of other consumers. The purpose of this study is to investigate the difference of consumers' purchase intention according to message sidedness of e-WOM, the expertise and tie strength of the sender, and to examine the interaction between recipient's regulatory focus and product involvement level of consumers, and to provide theoretical and practical implications. Nine hypotheses based on the previous literatures have been deduced in this study. To verify these hypotheses, an experiment are conducted through 2(two-sided message/one-sided message) x 2(strong/weak tie strength) x 2(high/low product involvement) x 2(high/low expertise of sender). The questionnaire is a scenario-based approach. Respondents contained 480 samples of consumers at all levels including close friends and relatives in China. The operation verification was conducted to examine whether the grouping of the message sidedness of e-WOM, expertise of sender, tie strength, regulatory focus and product involvement was suitable for the study. And the hypotheses were verified through ANOVA analysis. The results revealed that two-sided messages, high expertise of sender and strong tie strength had more positive effects on purchase intention. And the interaction effects of regulatory focus and product involvement were partly significant. This study has theoretical implications in that it extends the scope of e-WOM research by categorizing the characteristics of message sidedness, expertise of sender, tie strength, which are not covered in the previous research. In addition, while existing studies only focus on one-sided messages such as positive or negative information of WOM, this study suggests efficient uses of two-sided messages on a firm's product or service. Thus this study will be useful for practitioners who want to build successful strategies on online promotion.